Rocket systems can employ different engines and engine types that reflect the particular mission launch requirements as well as the types of payloads expected. In liquid-fueled engine configurations, fuel and oxidizer types can be selected according to energy needs, specific impulse characteristics, and other factors. However, the design and components used for rocket engines can vary considerably based upon the fuel and oxidizer selections. These components can include propellant tanks, feed lines, pumps, propellant injection components, and combustion chambers, among other components.
One example of a propellant configuration includes liquid oxygen (LOX)/propylene. LOX/propylene can provide potential performance greater than many other propellant combinations in terms of higher specific impulse and density due in part to the carbon double bond in propylene (a.k.a. propene) and the energy release associated with oxidation. Historically, LOX/propylene has not been a popular propellant in rocket engines, somewhat due to technical challenges with this propellant mix, as well as past industry infrastructure selections of other propellants that include hydrogen/LOX, rocket propellant-1 (RP-1)/LOX, LOX/methane, and various solid rocket propellants or hypergolic rocket propellants. However, various difficulties arise when using liquid propellants, such as injector erosion, chamber heat build-up, and potential for leaks in couplings and connections among the various piping and components of the engines.